textual economy in generation the SPUD system Magdalena Wolska 9 - - PowerPoint PPT Presentation

textual economy in generation the SPUD system

Magdalena Wolska

9 czerwca 2005 PTT 2005 – SPUD 2

assumption: generation is goal-oriented an agent has certain communicative intentions it aims to fulfill (e.g. identifying an entity, communicating a property

• f an entity)

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explicit means of goal satisfation: assemble appropriate syntactic constituents (e.g. entity: use np, action: use vb) textual economy: implicit goal satisfaction – exploit receiver’s recognition of inferential links to material elsewhere in sentence to fulfill independent goals

• verloading

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GRE: generating a description that characterizes the target entity uniquely

• input: an entity as specified by KB of information that is

presumed to be part of shared knowledge (common ground)

• output:

semantics of a linguistic description based on which the receiver of the information will be able to unambiguously distinguish the entity from other salient candidates (distractors) surface form that matches the conceptual material

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„economy” in GRE : generate a description D to indentify r in context set C just in case KB supports attribution of D to r and motivates D in describing r in C support: there must exist information that r fits the description (else description may not be understood or generated) motivation: there must be a reason to use each of the properties to describe r (else the generator may leave the desriptor out)

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• cf. full-brevity GRE: use as few properties as possible;

when multiple descriptions apply, f-b: produce a more complex description when shorter don’t refer uniquely r1 : the big black shaggy dog r1 : the affable purebred racing dog the black racing dog

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indredients of a GRE component:

• context set of entities that are explicit (or implicit) in

discourse

• formalisation of properties of these entities
• specification of how to combine the properties into

linguisitc description

• representation for processing
• reasoning to online assess how receiver will interpret the

given description resource intensive

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typical GRE scenario:

• any fact to be communicated must fit into abstract

grammatical structure (including lexical items)

• any reference to domain entity must be elaborated into a

description that uniquely identifies (cf. incremental descrption)

• surface form must be found

step-wise process

(assuming e in common ground, 1/ identify set of concepts that together distinguish e from its distractors, 2/ derive syntactic structure that realises these concepts)

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SPUD: perform syntactic and semantic processes simultaneously

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References

Matthew Stone and Bonnie Webber. Textual Economy through Close Coupling of Syntax and

• Semantics. Proceedings of INLG 1998, p. 178--187.

Martha E. Pollack. Overloading intentions for efficient practical reasoning. Nous 25(4):513--536. see also other references at: http://www.cs.rutgers.edu/~mdstone/nlg.html you can download SPUD at: http://www.cs.rutgers.edu/~mdstone/class/taglet/ (for instructions on running SPUD, you may contact Magdalena Wolska magda@coli.uni-sb.de)